Silicon ingots may be grown by the so-called Czochralski process in which a silicon ingot is pulled upward from a melt of silicon in a crystal puller apparatus. The process may be a continuous process in which silicon is intermittently or continuously added to the crucible as polycrystalline chunks or as pre-melted silicon or may be a batch process in which the ingot is withdrawn until silicon within the crucible is consumed.
Crystal pulling may be performed in the presence of an atmosphere within a housing of the puller, the atmosphere forming an interface with the melt. During continuous crystal pulling operations, the crucible erodes especially at the interface formed between the melt, the atmosphere and the crucible (i.e., the contact point). Erosion may degrade the crucible at the contact point to such an extent that the crucible becomes porous and solid particles may reach the growth zone from which the ingot is pulled. These solids degrade the lattice structure of the growing crystal and the growing process must be stopped due to degrading crystal yield.
A need exists for methods that involve reduction in the erosion rate at the crucible at the interface between the melt, the atmosphere and the crucible.
This section is intended to introduce the reader to various aspects of art that may be related to various aspects of the disclosure, which are described and/or claimed below. This discussion is believed to be helpful in providing the reader with background information to facilitate a better understanding of the various aspects of the present disclosure. Accordingly, it should be understood that these statements are to be read in this light, and not as admissions of prior art.